Hoegh-Guldberg et al. 2019. Science 10.1126/science.aaw6974  This figure illustrates the danger of the time lag involved in development and deployment at scale sufficient to make a difference in global temperatures. If we wait until the latter decades of this century to implement drawdown, overshoot will have caused irreversible damages to human and natural systems. 

Climate interventions are of two forms: those based on natural processes and those based on technology. Nature-based interventions involve the management of forests, agriculture, and wetlands. Technological solutions involve reducing global temperature through interception of solar radiation or direct removal of COthrough chemical means or with biofuels and carbon capture. In this module we will review the risks and possible advantages of the most likely forms of intervention.

It is obvious that climate change is the biggest challenge of this century and it is the gravest threat to humanity since we wandered out of Africa about 80,000 years ago. The existing burden of greenhouse gases in the atmosphere and the current rate of emissions requires us to remove carbon dioxide from the air. The goals of the Paris Agreement cannot be met without large scale long term withdrawals of carbon from the troposphere. Our situation is becoming urgent and geoengineering is likely because of political corruption and pressures from the fossil fuel and associated industries on legislatures. There are manifold risks associated with this approach to mitigation of climate change. Because geoengineering is likely to be a major factor in your lives and it has significant implications for human well being and all living systems on Earth, I am providing a module on the methods and prospective advantages and disadvantages. 

The IPCC and most other organizations concerned with mitigating climate change have long recognized the need for the drawdown of atmospheric CO2. The unusual thinking of policy makers has led them to call this drawdown “negative emissions” (this is truly bizarre if you think about it).  The scenarios to emerge from the UNFCCC Paris Agreement have scheduled drawdown to occur toward the end of this century, thus permitting a reduction in fossil emissions in a manner that it is hoped would minimize the putative near-term economic shock of shifting to a global economy based on renewables.

This is alarming because it means that the global average temperature will overshoot 2˚C (which is now recognized as the minimum Equilibrium Climate Sensitivity) for possibly 2-3 decades. This overshoot may cause several components of the Earth System to pass tipping points beyond which their return to their prior state will not be possible for millennia, if ever. Those parts include the Arctic sea ice, the Amazon Basin, the Arctic permafrost, and myriad ecosystems worldwide. The heat and continued acidification of the oceans and ecosystem disruptions resulting from breaching the 2˚C guardrail would be sufficient to cause widespread extinction of thousands of terrestrial and marine species. Despite all of the work at the COP26 and COP27, it is important to realize that the UNFCCC* has yet to bring forth a compelling plan for saving civilization and avoiding the most damaging effects of climate change. The moral hazard created by the industrialized nations has yet to be adequately addressed with respect to the losses and damages in the global south. 

The most alarming aspect of the development of geoengineering is the involvement of the petrostates such as Saudi Arabia, the UAE, Russia, and the fossil fuel majors and allied industries. Their interests are to maximize the use of fossil fuels through various proposals for how carbon dioxide can be captured and utilized.  Even more concerning is the financial conflict of interest that some scientists have because of their financial stake in the development of these technologies. While this approach may be attractive to some, deploying these technologies at sufficient scale to make a dent in the carbon burden of the atmosphere will incur huge costs in terms of the fossil fuels used to build them and expenditures of precious resources. Through tech-based geoengineering, the social costs of mining and using fossil fuels would continue producing numerous consequences for public health. 

The far simpler solution is to stop using fossil fuels as quickly as possible (this video is based on valid science). We must also begin appropriate measures to immediately extract CO2 from the air without any intention of further mining and production and burning of fossil fuels. There are several compelling analyses that show that renewables can meet our needs. For at least 40 years our leaders and scientists have known that use of renewable energy and killing the fossil fuel industry are our best hope.

The COVID-19 pandemic demonstrates is that the money and the will can be found for monumental change when our leadership decides to make it happen. We have been told for decades why we can’t quit fossil fuels because it would be too expensive and damage the economy, yet it is clear that massive resources can be mobilized for an emergency when deemed necessary. Climate change is and has been such an emergency at least since 1981 when the anthropogenic signal emerged from the background noise of the climate (James Hansen et al. 1981. Science).

Abdication of the moral responsibility for climate change by the United States will go down in history as one of the most heinous acts by a single nation. According to a report in Nature in September 2019, the US is responsible for about 20-25 percent of the cumulative emissions in the atmosphere. Collectively, the other more than 190 nations are responsible for the remainder with China being the largest single nation contributor at 13-15 percent. A 2021 report from CarbonBrief quantifies the responsibility of the US for the majority of emissions since 1850.

Rather than lead the world in addressing the climate crisis, one of the two major political parties of the United States continues to block actions to address climate change by reducing fossil fuel emission. Rather than denying the reality of climate change, which is now blatantly absurd, these political actors and their allied industries and corporations continue to delay the urgent actions needed to stop emissions. The fossil fuel industry in the US has long been at war with climate science despite knowing the dangers since the 1970s. Recently there has been bipartisan approval of investing billions in carbon capture utilization and storage (CCUS). This profane video points out the flawed economics and failed technology of this approach, which to date has failed to capture even a small fraction of emissions. Despite the dark humor, the science in this video (including emissions from blue hydrogen) is solid). 

Equally important to ending the use of fossil fuels and managing drawdown is the urgent need to holistically and intelligently manage ecosystems for maintenance of biodiversity and carbon sequestration. Failure to halt the destruction of ecosystems, especially tropical forests, will result in large, long-term releases of carbon and significant positive feedback on the climate system. Management of ecosystems based on narrow old-school concepts of eradicating alien and invasive species is doomed to failure as ecosystems change within decades, rather than centuries or millennia. It is urgent that we develop modern working definitions of ecosystem form and function based on the dynamic nature of species vicariance and climate change. How we treat human and non-human climate migrants and the ecosystems we all inhabit will literally determine the fate of humanity.

– Stephen Mulkey 17 March 2023. The views expressed here are my opinion and shared perspective of thousands of scientists, but based on history, do not reflect the views of the University of Florida or the government of the State of Florida. 

*Reminder: The body responsible for producing agreements for global mitigation and adaptation is the UNFCCC, not the IPCC. The IPCC provides science, data, and scenarios. The UNFCCC organizes the annual Conference of the Parties (COP) where agreements are hammered out. 

Menu for carbon dioxide removal. CO2 is the only greenhouse gas which is generally feasible to remove from the troposphere. The others exist at parts per billion or even parts per trillion. Although CO2 is in the atmosphere at parts per million (0.04%) the mechanisms for natural fixation have existed on Earth for billions of years. Removal through tech-based geoengineering has yet to be demonstrated as feasible at large scale. Almost all attempts at carbon capture and sequestration to date have failed to deliver as intended or simply failed to function entirely. This figure (sans highlighting) is from Chapter 12 of the AR6, WG III. The lead of two coordinating authors of this chapter is Mustafa Babiker, an economist employed by the Saudi Arabian Oil Company (Saudi Aramco). The Saudi and UAE governments along with the fossil fuel majors in the US have been strong proponents of tech-based geoengineering.